1. Field of the Invention
The invention relates to a pneumatically actuated switching device for a patient call system. More specifically, the invention relates to a switch assembly comprising a pneumatic hose connection member for connecting the pneumatic hose to the housing of the switch assembly for operation of the switch assembly of the pneumatically actuated switching device.
2. Description of the Prior Art
Hospitals and other patient-care institutions frequently provide patient call systems wherein a patient may activate a signal to a central station, such as a nurse's station, to summon assistance. The use of conventional electrical switches to generate the signal in such environments is undesirable given the potentially combustible levels of oxygen that may be present near the patient area.
An alternative to conventional electrical switches involves the use of a pneumatically actuated switching device which utilizes a pulse of pressurized air to actuate a signal circuit and which avoids the safety concerns associated with the conventional electrical switch. Such pneumatically actuated switching devices are particularly beneficial where combustion concerns are present, such as, for example, in oxygen rich environments since the construction of the pneumatically actuated switching device limits the possibility of electrical arcing which is a problem associated with conventional electrical switches.
U.S. Pat. No. 3,823,285 to Dwyer illustrates an example of a pneumatically actuated switching device having a deformable pneumatic actuated bulb for a patient actuated nurse call system. The deformable pneumatic actuated bulb provides a source of pressurized air to operate a switching circuit which generates an electrical signal. This system is well suited for use in environments where it is undesirable to use a conventional electrical switch for the reasons discussed in the preceding paragraphs. The pneumatically actuated switching device comprises an electrically conductive sleeve having a bore and a conductive ball in the bore which is movable in response to pneumatic pressure. The other end of the bore is in communication with a pneumatic hose or tube which is connected to a source of pneumatic pressure, such as the deformable pneumatic actuated bulb. Two conductors are adapted to be connected to two sides of an electrical circuit. The first conductor is in electrical communication with the sleeve and the second conductor is mounted in an opening in the sleeve which extends into the bore. The ball is movable between a circuit open position out of electrical communication with the second conductor and a circuit closed position in electrical communication with the second conductor and the sleeve. A cam surface extends into the bore and into the path of the ball and cams the ball into electrical communication with the second conductor and the sleeve in the circuit closed position. The sleeve normally is oriented generally vertically, although the device operates satisfactorily when the sleeve is oriented horizontally in that the ball moves in the bore with very little, if any, friction.
U.S. Pat. No. 5,155,309 to Dwyer illustrates a further example of a pneumatically actuated switching device which comprises a pneumatic bulb having an annular ring configuration with a convexly shaped actuator dome resembling a doughnut to provide a distinctive identification to the bulb for distinction from other pneumatic bulbs that may be utilized for different purposes in a patient area. A base plate includes protruding truncated conical members relied upon to maintain the doughnut shaped actuator at a fixed location on a patient's mattress so that the patient can find the deformable pneumatic bulb to summon assistance.
U.S. Pat. No. 5,736,702 to Roberts, et al. discloses a still further example of a pneumatically actuated switching device. A housing connection provides for optional assembly orientations, i.e. an in-line assembly configuration for the switch housing and a right angle configuration for the switch housing relative to a jack for electrical connection with a receptacle of a patient call system. The optional assembly orientations are brought about via a connector which is partially enclosed within a cavity formed in an end of the housing. The connector and the switch housing of this pneumatically actuated switching device is generally glued together once the pins are in the appropriate openings for forming a desired angular orientation of the connector relative to the housing.
These above pneumatically actuated switching devices in general have a pneumatic hose or tube connected at its one end to the switch assembly and connected at its other end to the deformable pneumatic bulb for delivering pressurized or compressed air to the switch assembly for activation of the switch assembly which sends an electrical signal to the patient call system. In general, the pneumatic hose of these prior art devices are attached to the housing of the switch assembly via a connector member and mechanical devices, such as, for example, pins or via a connector member which is shrink or pressed fitted to the housing with the pneumatic hose being wedged into the connector member. The connector member in some instances may become loosened and/or may become disconnected from the housing of the switch device, resulting in the loss of pressurized air for operation of the switch assembly.
There is therefore a need in the art to provide an improved design for connecting a connection member for attaching a pneumatic hose to a housing of a switch assembly in a pneumatically actuated switching device.
There is a further need in the art to provide a connection member for attaching a pneumatic hose to a housing of a switch assembly in a pneumatically actuated switching device which is easy to install and/or remove and which is not easily dislodged from the housing.